5SFE: Nasty High Idle=(Please Help!

[mr3]

Have you bled your coolant lately? Have you checked the levels? The pulsing seems to me like you have an air bubble trapped somewhere that needs to be burped out.

[goddom]

I just found with mine that the one of the wires in the wire harness for the idle control valve was worn through. So, I would suggest everyone check the wire harnesses before doing anything drastic. I am going to fix this today, so I will see if that fixes my problem and let you guys know.

[DZ91MR2]

Originally Posted by mr3

Have you bled your coolant lately? Have you checked the levels? The pulsing seems to me like you have an air bubble trapped somewhere that needs to be burped out.

No I havent. and It only seems to do it everyonce and a while. it doesnt do it all the time...

[Kayo92MR2]

I concluded that the IAC was bad because i took it apart and cleaned it and my idle did not change, my throttle body was clean so i took the hose going to my IAC valve and plugged it and the idle dropped down to 1100....still not perfect but better than 2500.

[goddom]

So far, no luck for me. I covered the TB while the car was running, and it didn't stall. So there must be an air leak somewhere in the TB or intake manifold. My primary suspect now is EGR valve since I can't see anything else that connects to the intake that might be leaking air. Also I am getting some low popping in the exhaust that may also be linked to the EGR.

[Kayo92MR2]

Now that my idle has dropped down i have noticed a popping sound also, i thought it was missing every once and a while but it doesnt do it while driving. Something wrong with the EGR system could cause that stumble or popping as you described it?

[goddom]

I was hoping it was the EGR, but when I removed it, it didn't seem to help that at all. I removed my AC idle up switch and that seemed to drop the idle by about 200 rpms, so I am at 1250 now.

I now think that I have a leak in the intake manifold gasket. I need to test it with carb cleaner before pulling the manifold off and replacing the gasket.

[Kayo92MR2]

I just took off my AC pulley and now the idle seems to be fixed. After it warms up it idles around 700 to 900. But i think my timing is off a little bit because when im down shifting to a stop sign it backfires a little bit and my car seems to be lacking in the top end on the freeway.

[DZ91MR2]

Mine is lacking bottom end hard core like its bad to the point it feels like I hit nitrious when I hit 4500-5000rpm then it pulls hard. but weak in the lower rpms...

[Kayo92MR2]

I thought it was just my 5-sfe, my car is boggy through 3500 then like DZ91MR2 said it almost feels like you hit nitrous. I had assumed it was something wrong with my engine and no one else had this problem. I just bought this car not a month ago and it seems like the problems just keep coming. My speedo just quite working on top of all this. im thinking speed sensor? Are they electronic or controled by a cable?

[DZ91MR2]

thats EXACTLY what mine is doing its slow then turns boggy then boom like I hit boost or something... I know im planning on getting a new motor anyway but that could be awhile so if anyone knows whats up I could really us the help!

[lmp9002002]

Ok i got a few questions to answer here.
For one, it's a cable speedo. Thats why some of the older ones bounce around a bit.
For the "nitrous" feeling, it's a misfire. I had the same issue, my golden RPM was 4k- noticed soo many times cruising at about 75-85 in 5th gear that as soon as i hit 80 (4k in 5th gear) it threw me back into my seat.
Since then i've replaced my timing belt and plug wires, and the problem is gone. My guess would probably be the timing belt. a lot of people neglect that.. And with the mr2 being as old as it is, a lot have developed oil leaks, whether its at the front seal or valve cover gasket. I had both and had a lot of oil on the timing belt- which led to its deterioration.

[lmp9002002]

Originally Posted by Kayo92MR2

I just took off my AC pulley and now the idle seems to be fixed. After it warms up it idles around 700 to 900. But i think my timing is off a little bit because when im down shifting to a stop sign it backfires a little bit and my car seems to be lacking in the top end on the freeway.

By the way, from experience and from learning from someone that's been driving manuals for 40+ years, don't downshift to stop. Keep it in whatever gear your in until it pops out, then just brake while the car is in neutral. It's much smoother, and much less wear on the motor (and clutch, mainly).

[Kayo92MR2]

Hmm i didnt know it would pop out? i thought it would just kill if you tried to come to a stop in fifth. Well im eger to try that because i would assume you have to be a VERY low RPM's for it to pop out of gear.

[lmp9002002]

Originally Posted by Kayo92MR2

Hmm i didnt know it would pop out? i thought it would just kill if you tried to come to a stop in fifth. Well im eger to try that because i would assume you have to be a VERY low RPM's for it to pop out of gear.

it pops out without the clutch when the car is at idle RPM for that gear. on my car, in 5th gear, it pops out around 20 (my idle is 750-950). Since you said your idle is high, start putting a small amount of pressure on the shifter when you get around 30, and it should just pop right out. if it gets below 20, just put the clutch in and shift into neutral.

[Kayo92MR2]

Ok so Imp9002002, back to the speedometer question. If its a cable is there a speed sensor in the back by the wheel that could have went bad? If not how should i go about checking the cable?

[lmp9002002]

Not entirely sure. Mine has the bouncing issue, but still works so i haven't bothered messing with it yet. But, luckily there is a sticky with some very useful info:
91-92 speedometer problems? info here

[DZ91MR2]

Originally Posted by lmp9002002

By the way, from experience and from learning from someone that's been driving manuals for 40+ years, don't downshift to stop. Keep it in whatever gear your in until it pops out, then just brake while the car is in neutral. It's much smoother, and much less wear on the motor (and clutch, mainly).

I never really down shift when im stopping I just put it in neutral myself and brake. Idk always seemed to save a little gas doing that.. lol but hey I do have a valve cover gasket leak. do you think if it fixed this and got my timing belt changed this would solve my problems?

[DZ91MR2]

Also I thought I would add that my Gauges are still working but the light does not so im blind at night lol and my cruise control does not work just incase anything like that could be effecting anything else as well... or a side effect to some other problem..

[lmp9002002]

Originally Posted by DZ91MR2

I never really down shift when im stopping I just put it in neutral myself and brake. Idk always seemed to save a little gas doing that.. lol but hey I do have a valve cover gasket leak. do you think if it fixed this and got my timing belt changed this would solve my problems?

Keep it in gear until it reaches idle. The motor helps to brake the car that way, so your brakes will last longer.
Your valve cover gasket leak is likely leaking oil onto the timing belt, which causes it to wear out much more quickly. So yes, a VC gasket change and a timing belt change would probably help your idle.